1. Field of the Invention
The present invention relates to a compact dual-mode manual pump such as for inflating and that in one mode provides a low pressure of air per pump stroke and in another mode provides a high pressure per stroke.
2. Description of the Related Art
Taiwan patent No. 228,257 discloses a pump including a head, an air duct connected with the head, a first cylinder, and a second cylinder. A valve joint is formed on an end of the head for connecting with a valve of a tire. The first cylinder is tubular and movable axially with respect to the air duct. The second cylinder receives and is movable axially with respect to the first cylinder. The air duct, the first and second cylinders form a tripartite telescopic design. A base formed in the second cylinder is selectable to couple with a base formed in the first cylinder to prove the pump to be selectable between low pressure and high pressure pumping modes.
However, this pump suffers some problems. One problem is that the first cylinder must be received in the second cylinder and the two bases must be coupled with each other to switch low pressure and high pressure pumping modes. It is time consuming to switch the pump between the two modes and any time loss would be crucial for a rider who is using the pump during the racing competition. Another problem is that the pump having a longer length so that using the pump in a narrow space is inconvenient.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.